Note 12 - Fair Value Measurements - Assets and Liabilities Measured at Fair Value On a Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Assets measured at a fair value on a recurring basis	$ 529,953	$ 589,851
Liabilities measured at a fair value on a recurring basis	94	747
Interest Rate Swap [Member] | Derivative Financial Instruments, Liabilities [Member]
Liabilities measured at a fair value on a recurring basis	23	692
Mortgage Banking Derivative [Member] | Derivative Financial Instruments, Liabilities [Member]
Liabilities measured at a fair value on a recurring basis	71	55
Derivative Financial Instruments, Assets [Member] | Interest Rate Swap [Member]
Assets measured at a fair value on a recurring basis	486
US Government Agencies Debt Securities [Member]
Assets measured at a fair value on a recurring basis	147,908	106,142
Residential Mortgage Backed Securities [Member]
Assets measured at a fair value on a recurring basis	296,925	326,239
US States and Political Subdivisions Debt Securities [Member]
Assets measured at a fair value on a recurring basis	44,609	95,930
Corporate Debt Securities [Member]
Assets measured at a fair value on a recurring basis	10,147	9,579
Equity Securities [Member]
Assets measured at a fair value on a recurring basis	218	218
Residential Mortgage Loan Long Term [Member]
Assets measured at a fair value on a recurring basis	29,567	51,629
Mortgage Banking Derivative [Member]
Assets measured at a fair value on a recurring basis	93	114
Fair Value, Inputs, Level 1 [Member]
Assets measured at a fair value on a recurring basis
Liabilities measured at a fair value on a recurring basis
Fair Value, Inputs, Level 1 [Member] | Interest Rate Swap [Member] | Derivative Financial Instruments, Liabilities [Member]
Liabilities measured at a fair value on a recurring basis
Fair Value, Inputs, Level 1 [Member] | Mortgage Banking Derivative [Member] | Derivative Financial Instruments, Liabilities [Member]
Liabilities measured at a fair value on a recurring basis
Fair Value, Inputs, Level 1 [Member] | Derivative Financial Instruments, Assets [Member] | Interest Rate Swap [Member]
Assets measured at a fair value on a recurring basis
Fair Value, Inputs, Level 1 [Member] | US Government Agencies Debt Securities [Member]
Assets measured at a fair value on a recurring basis
Fair Value, Inputs, Level 1 [Member] | Residential Mortgage Backed Securities [Member]
Assets measured at a fair value on a recurring basis
Fair Value, Inputs, Level 1 [Member] | US States and Political Subdivisions Debt Securities [Member]
Assets measured at a fair value on a recurring basis
Fair Value, Inputs, Level 1 [Member] | Corporate Debt Securities [Member]
Assets measured at a fair value on a recurring basis
Fair Value, Inputs, Level 1 [Member] | Equity Securities [Member]
Assets measured at a fair value on a recurring basis
Fair Value, Inputs, Level 1 [Member] | Residential Mortgage Loan Long Term [Member]
Assets measured at a fair value on a recurring basis
Fair Value, Inputs, Level 1 [Member] | Mortgage Banking Derivative [Member]
Assets measured at a fair value on a recurring basis
Fair Value, Inputs, Level 2 [Member]
Assets measured at a fair value on a recurring basis	528,142	588,019
Liabilities measured at a fair value on a recurring basis	23	692
Fair Value, Inputs, Level 2 [Member] | Interest Rate Swap [Member] | Derivative Financial Instruments, Liabilities [Member]
Liabilities measured at a fair value on a recurring basis	23	692
Fair Value, Inputs, Level 2 [Member] | Mortgage Banking Derivative [Member] | Derivative Financial Instruments, Liabilities [Member]
Liabilities measured at a fair value on a recurring basis
Fair Value, Inputs, Level 2 [Member] | Derivative Financial Instruments, Assets [Member] | Interest Rate Swap [Member]
Assets measured at a fair value on a recurring basis	486
Fair Value, Inputs, Level 2 [Member] | US Government Agencies Debt Securities [Member]
Assets measured at a fair value on a recurring basis	147,908	106,142
Fair Value, Inputs, Level 2 [Member] | Residential Mortgage Backed Securities [Member]
Assets measured at a fair value on a recurring basis	296,925	326,239
Fair Value, Inputs, Level 2 [Member] | US States and Political Subdivisions Debt Securities [Member]
Assets measured at a fair value on a recurring basis	44,609	95,930
Fair Value, Inputs, Level 2 [Member] | Corporate Debt Securities [Member]
Assets measured at a fair value on a recurring basis	8,647	8,079
Fair Value, Inputs, Level 2 [Member] | Equity Securities [Member]
Assets measured at a fair value on a recurring basis
Fair Value, Inputs, Level 2 [Member] | Residential Mortgage Loan Long Term [Member]
Assets measured at a fair value on a recurring basis	29,567	51,629
Fair Value, Inputs, Level 2 [Member] | Mortgage Banking Derivative [Member]
Assets measured at a fair value on a recurring basis
Fair Value, Inputs, Level 3 [Member]
Assets measured at a fair value on a recurring basis	1,811	1,832
Liabilities measured at a fair value on a recurring basis	71	55
Fair Value, Inputs, Level 3 [Member] | Interest Rate Swap [Member] | Derivative Financial Instruments, Liabilities [Member]
Liabilities measured at a fair value on a recurring basis
Fair Value, Inputs, Level 3 [Member] | Mortgage Banking Derivative [Member] | Derivative Financial Instruments, Liabilities [Member]
Liabilities measured at a fair value on a recurring basis	71	55
Fair Value, Inputs, Level 3 [Member] | Derivative Financial Instruments, Assets [Member] | Interest Rate Swap [Member]
Assets measured at a fair value on a recurring basis
Fair Value, Inputs, Level 3 [Member] | US Government Agencies Debt Securities [Member]
Assets measured at a fair value on a recurring basis
Fair Value, Inputs, Level 3 [Member] | Residential Mortgage Backed Securities [Member]
Assets measured at a fair value on a recurring basis
Fair Value, Inputs, Level 3 [Member] | US States and Political Subdivisions Debt Securities [Member]
Assets measured at a fair value on a recurring basis
Fair Value, Inputs, Level 3 [Member] | Corporate Debt Securities [Member]
Assets measured at a fair value on a recurring basis	1,500	1,500
Fair Value, Inputs, Level 3 [Member] | Equity Securities [Member]
Assets measured at a fair value on a recurring basis	218	218
Fair Value, Inputs, Level 3 [Member] | Residential Mortgage Loan Long Term [Member]
Assets measured at a fair value on a recurring basis
Fair Value, Inputs, Level 3 [Member] | Mortgage Banking Derivative [Member]
Assets measured at a fair value on a recurring basis	$ 93	$ 114